09 April 2011

The naked penguin problem

For the last few years, a mysterious feather-loss disorder has been affecting penguin chicks on both sides of the Atlantic. The appearance of these "naked" penguins has scientists puzzled as to what could be causing the condition.

The disorder, which can result in smaller chicks and increased mortality, has been observed in both African and Magellanic penguin chicks. A study on the disorder by researchers from the Wildlife Conservation Society (WCS) and the University of Washington, South African Foundation for the Conservation of Coastal Birds (SANCCOB) and Centro Nacional Patagónico appeared in a recent edition of the journal Waterbirds.

"Feather-loss disorders are uncommon in most bird species, and we need to conduct further study to determine the cause of the disorder and if this is in fact spreading to other penguin species," said Professor Dee Boersma, who has conducted studies on Magellanic penguins for more than three decades.

The feather-loss disorder first emerged in Cape Town, South Africa, in 2006, when SANCCOB researchers observed it in African penguins in a rehabilitation center. During that year, approximately 59% of the penguin chicks at the facility lost their feathers, followed by 97% of the chicks at the facility in 2007, and 20% of the chicks in 2008. Chicks with feather-loss disorder eventually began to grow new feathers, but it was discovered that they took longer to grow to a size deemed suitable for release into the wild.

On the other side of the South Atlantic, researchers from WCS and the University of Washington observed feather-loss disorder in the chicks of wild Magellanic penguins (closely related to African penguins) for the first time in 2007 in four different study sites along Argentina’s coastline. Researchers also noted that while feathered chicks sought out shade in the hot midday sun, featherless chicks remained in the sun’s glare. Several of the chicks with feather-loss disorder died during the study.

In both instances, penguin chicks with feather-loss disorder grew more slowly and were smaller in size and weight than feathered chicks. The disparities were due to the increased energy spent by the featherless chicks in keeping warm in the absence of an insulating coat of feathers and/or down. So far, the possible causes include pathogens, thyroid disorders, nutrient imbalances or genetics.

"The recent emergence of feather-loss disorder in wild bird populations suggests that the disorder is something new," said Mariana Varese, Acting Director of WCS's Latin America and Caribbean Program. "More study of this malady can help identify the root cause, which in turn will help illuminate possible solutions."

"We need to learn how to stop the spread of feather-loss disorder, as penguins already have problems with oil pollution and climate variation," said Professor Boersma. "It’s important to keep disease from being added to the list of threats they face."

Source
"Naked" penguins baffle experts, 7 April 2011, Wildlife Conservation Society

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